Sliding vane rotary engines and process for obtaining high torque power

ABSTRACT

The process consists in obtaining high torque, rotary power from initial (high energy) fragments of expansion-produced work which is obtained by allowing just a limited pressure-drop of successive segments of a highly expansible gas. The rest of the work which could be obtained from more complete expansion may be extracted in some other way, as by segmental expansion in successive chambers and/or by it driving a turbine, and then these secondary outputs may be added to the first. Thus, in comparison with the output curve of the full stroke of a piston engine, here only the initial, nearly vertical segment of the total expansion curve is &#39;&#39;&#39;&#39;severed&#39;&#39;&#39;&#39; from the whole and is used to pace at high torque, a rotary drive shaft. Structurally, this is by the use of one or more successive, shallow, arcuately elongated, curcumferential-stepwise expansion chambers in a sliding vane, rotary engine, in place of the wedge-shaped chambers of the past. The latter resulted in low-torque output partly because they tried to expose as large as possible a contact area of the sliding vane, and the associated outward or radial gas-expansion in the wedge-chamber produced no obtainable work from such radial movement; also, the intended, nearly complete gas-expansion resulted in an &#39;&#39;&#39;&#39;average&#39;&#39;&#39;&#39; low-torque output because most of it was obtained from the flat end of the pressure-volume curve. The present process is applicable to both internal combustion and non-combustion (e.g. compressed air or steam) rotary engines of the sliding vane type, for which several new constructions are provided. Advantage is also obtained by use of a molded carbon facing for the rotor and the combustion chambers.

United States Patent [191 Takitani May 7,1974

[ SLIDING VANE ROTARY ENGINES AND PROCESS FOR OBTAINING HIGH TORQUE POWER [76] Inventor: I-Iideo Takitani, 200 S. Makapu St.,

Kahului, Hawaii 96732 [22] Filed: Jan. 28, 1972 [21] Appl. No.: 221,572

Related US. Application Data [63] Continuation-impart of Ser. No. 4,799, Jan. 22,

1970, abandoned, which is a continuation-in-part of Ser. No. 752,961, Aug. 15, 1968, abandoned.

[52] US. Cl 123/8.07, 60/13, 60/15, 123/2, 123/8.09, 123/8.l5,123/8.45, 418/13, 418/178, 418/152, 418/179 [51] Int. Cl. F02b 53/10 [58] Field of Search 418/260, 152, 13,- 178, 418/179; 123/8.09, 8.07, 8.15, 8.45, 2;

Primary ExaminerClarence R. Gordon Attorney, Agent, or FirmI-Ioward L. Johnson [57 ABSTRACT The process consists in obtaining high torque, rotary power from initial (high energy) fragments of expansion-produced work which is obtained by allowing just a limited pressure-drop of successive segments of a highly expansible gas. The rest of the work which could be obtained from more complete expansion may be extracted in some other way, as by segmental expansion in successive chambers and/or by it driving a turbine, and then these secondary outputs may be added to the first. Thus, in comparison with the output curve of the full stroke of a piston engine, here only the initial, nearly vertical segment of the total expansion curve is severed from the whole and is used to pace at high torque, a rotary drive shaft. Structurally, this is by the use of one or more successive, shallow, arcuately elongated, curcumferential-stepwise expansion chambers in a sliding vane, rotary engine, in place of the wedge-shaped chambers of the past. The latter resulted in low-torque output partly because they tried to expose as large as possible a contact area of the sliding vane, and the associated outward or radial gasexpansion in the wedge-chamber produced no obtainable work from such radial movement; also, the intended, nearly complete gas-expansion resulted in an average low-torque output because most of it was obtained from the flat end of the pressure-volume curve. The present process is applicable to both internal combustion and non-combustion (e.g. compressed air or steam) rotary engines of the sliding vane type, for which several new constructions are provided. Advantage is also obtained by use of a molded carbon facing for the rotor and the combustion chambers.

17 Claims, 12 Drawing Figures PATENTEDIAY 101 3.809.020

SHEET 1 OF 4 INVENTOR. H7050 fl/r/rA/v/ f WW PATENTEnm 1 1914 3.809.020 sum 2 UP 4 @IFQ $11072 INVENTOR. M050 JIM/721w SLIDING VANE ROTARY ENGINES AND PROCESS FOR OBTAINING HIGH TORQUE POWER This is a continuation-in-part of Ser. No. 4799, filed Jan. 22, 1970, now abandoned which is a continuationin-part of Ser. No. 752,961, filed Aug. 15, 1968, now abandoned.

BACKGROUND OF THE INVENTION Internal combustion engines of the rotary type are considered to gas-contacting more efficient than piston-type engines, that is, they extract a higher percentage of the potential energy which is available in the fuel or source of power. Essentially a rotary engine provides a cylindrical rotor carrying a peripheral series of radially sliding vanes, within a surrounding casing which provides series of (a) decreasing volume chambers (for compression) and, starting at an ignition point, (b) increasing volume chambers (for explosion-expansion), which chambers are swept or wiped by successive vanes, each pair of vanes thus defining a closed volume of gas which it moves or which moves it (the expansion phase turning the power output shaft). Within the expansion chambers, the gas-containing faces or exposed tips of the vanes act as pistons in effecting annular movement of the rotor and its axial drive shaft by reason of the thrust of the expansible gas against the vane. Such compressed gas is allowed to expand by reason of the forward vane moving into a progressively larger chamber. As noted in the preceding abstract, in the past such expansion chambers have generally been wedge-shaped, and thus as increased area of the vane tip becomes exposed due to its outward (radial) movement in the outwardly increasing chamber, the gas pressure on it diminishes; and in addition, the outward expansion of this gas does no useful work. Further, if nearly complete expansion of the gas was permitted before being vented (in order to extract nearly all of the possible work), the output was low torque, even at comparatively high speed. In fact, this seems to be almost an inevitable result with past constructions based on relatively complete gas expansion, which in addition is generally carried out in a single chamber.

As a further analogy, it is recognised that the greater fragment of power obtained from a single expansion of a piston in an engine, is obtained from the initial fraction such as the first one-fourth or one-eighth of the expansion. The proportion rapidly decreases as the piston approaches the end of the chamber, as seen from FIG.

8. It is here submitted, that a similar effect must be recognised in the customary expansion cycle ofa rotary engine, and that if the gas pressure is allowed to drop nearly to the possible minimum (which would be atmospheric pressure) before being vented, in order to obtain maximum efficiency" the torque obtained from the rotor is necessarily the average of all of these decreasing fractions of a single-chamber or nearly complete" expansion; it is therefor necessarily and inevitably low torque. In contrast, if only the initial fraction of (possible) expansion of the high pressure gas is continuously applied to (or used to pace) the rotor (even though the rest is vented or otherwise diverted as into a turbine), this initial small fraction of power will impart high torque to the rotor. Structurally such result may be obtained by employing (in place of a wedge-shaped single chamber) a series of shallow, step-wise expanding-lengthwise chambers which in their total, still employ only the initial fragment of possible expansion, or use such segments to continually pace the rotor, by sequential application. However advantage may be obtained from single chamber expansion, especially when such expansion is limited to the initial fragment such as one-eighth or one-fourth of the possible volume expansion.

Accordingly one example of the present, new rotary engine construction provides a stepwise multi-chamber expansion for each discrete charge or explosioncombustion, the several successive expansion stages or chambers being formed by shallow, elongated, generally polygonal casing recesses which are arcuately curved from the rotor axis and may be so constructed as to permit substantially immediately complete or maximum radial extension of the vane therein at the beginning of each chamber. In other words, the maximum piston area or exposed face of the vane is presented at the beginning of each expansion stage, rather than progressively; and a high pressure is retained by the shallowness of the steps or the limited expansion permitted by the successive chambers.

Also, use of such limited pressure-drop principle is not limited to internal combustion engines. High pressure gas which is not the direct result of explosive combustion may be used, for example steam or compressed air, or underground deposits of expansible gas can be tapped. Only an initial fragmental reduction of such high pressure is applied to the rotor in a continuous sequence adapted to pace it continuously at high torque. In this connection there is provided a noncombustion rotary engine construction wherein successive rotary segments of the rotor are turned (a) by high pressure gas without appreciable reduction of pressure, the vanes acting first to sever segments of the pressurized feed, and then (b) by a successive expansion permitting partial pressure reduction (expansion) of the gas so as to extract more work from it without major pressure-drop.

BRIEF STATEMENT OF THE INVENTION By using only the initial fragment or fraction of highly compressed and hence highly expansible gas (whether obtained by simultaneous explosive combustion as in an internal combustion engine, or starting with gas already compressed by pump action or by natural forces), the energy of such expanding, small fraction can be converted to high-torque, rotary energy under controlled conditions. The lower-torque energy obtainable from further expansion can simply be otherwise employed since it is still high-pressure gas; thus the latter can be utilized to drive a turbine, and the power can be added to the same rotary drive shaft which is already being paced by the successive severed" fractions of high-torque energy. Structurally such energy is embodied in a rotary output shaft by use of sliding vane rotary engines, of which several which utilize the present pr0- cess are here presented (of both internal combustion and non-combustion types) which are characterized by a sequence in the gas expansion cycle, of elongated, shallow, arcuate cavities having stepwise increases in volume (in contrast to wedge-shaped chambers of the prior art).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partly elevational and partly diametric sectional view taken through one embodiment of a sliding FIG. 2 is a generally axial, sectional view taken along the line 22 of FIG. 1 with parts appearing in eleva- 1 tion, and the blower shown schematically.

FIG. 3 is an enlarged sectional detail of a fragment of the structure of FIG. 1, showing the immediate area of the firing chamber.

FIG. 4 is a diametric sectional view through another embodiment of the invention, which is an internal combustion, sliding vane, rotary engine having a single expansion chamber from which the gaseous combustion product may be expelled to a turbine while still under high pressure.

FIG. 5 is a cross section taken along the line 5-5 of FIG. 4 and particularly showing in the area of the ignition element, the passage thereformed in the casing adjacent the end of the moving vane, which is located so as transiently to bypass the tip of the vane and thus allow part of the ignited fuel from the forward expansion chamber to also expand rearward so as to further compress the preceding charge of compressed but previously unignited fuel mixture FIG. 6 is a diametric sectional view through a twostage non-combustion rotary engine which is operated from an external source of compressed gas or steam.

FIG. 7 is a diametric section taken through a dual, three-stage non-combustion rotary engine which has two stepwise expansion chambers in each stage.

FIG. 8 is an air-standard Pressure-Volume diagram showing, for comparison with the present rotor engines, how the pressure decreases with increasing expansion in a piston-engine chamber.

FIG; 9 is an axial sectional view, partly in elevation, taken along line 9-9 of FIG. 10 through another form of internal combustion engine embodying the present invention wherein one diametrically truncated half of the rotor unit carries the combustion phase, and the other half carries the compression phase, and the indrawn current of fuel-air mixture from the carburetor is first passed transversely through the rotor to effect heat exchange. I

FIG. 10 is a transverse sectional view taken along the line l0 10 of FIG. 9, with part of the face plate of the combustion half of the rotor broken away.

FIG. 1 l is a transverse sectional view taken along the line 1 ll l of FIG. 9, through the compression half of the rotor.

FIG. 12 is a modification of FIG. 4 with two combustion chambers.

Looking first at the pressure-volume curve for full stroke displacement of a piston in a combustion chamber (FIG. 8), it becomes apparent how the pressure falls off rapidly as the volume (i.e. length of stroke) increases. After the initial, almost vertical peak of the curve, the pressure (which equates with output) drops very fast with very little further expansion of volume; it practically flatens out before the midpoint of the stroke. Hence if only the high pressure portion were used, a piston engine run with just these initial segments of a full stroke, would be a much more powerful engine (although less efficient if all the potential energy is not harnessed). Now in a rotary engine, the protruding tip of the sliding vane which is pushed" by the expanding gas is analogous to a piston. If it is impelled only by high pressure gas, that is by the primary explosion-burst (figuratively speaking) without much pressure-drop or volume-expansion, the force imparted to the piston-like vane will be correspondingly greater. With the present shallow expansion chamber construction, such result is obtainable with sliding vane rotary engines. Accordingly it will be realized that the advantage is not a matter of the absolute high pressure that is used, but rather of how it is used.

In the embodiment of FIGS. 1-3, a generally cylindrical casing or housing 10 is formed with two identical, clockwise halves, each structured for a complete cycle of compression-expansion. Each half has inlet 12 and outlet 14 ports, a socket 16 for removable insertion of a spark plug 18, plus generally radially projecting external fins 20 for heat dissipation, and a blower passage 17, 19 for circulation of cooling air across the rotor edge at end of cycle, as by a blower 23. The inlet port 12 is coupled to a carburetor 22 by a supply conduit 13. The outlet 14 may be vented directly to the atmosphere, if desired, through a muffler or filtering unit (not shown); or the exhaust stream may operate a compressor 15 which is connected to the inlet 12) of the next cycle as by conduit 21.

The casing 10 encloses a generally annular cavity 11 and is formed essentially of an irregularly curved, inner side wall 24 which joins together a pair of approximately disk-shaped, parallel, end walls 25, 26, the latter axially carrying raceways 27, 28, which jointly journal an output shaft 30. An enlarged hub 32 of the shaft is located between the pair of end walls 25, 26, and is longitudinally splined at 33 to the body of a cylindrical rotor 34. The rotor is formed with a plurality of diametrically aligned or radially directed guideways 35, each projecting outward from the hub and terminating in a narrower open-ended slot portion 36.

A generally flat-sided vane 37 is slidingly located in each outer slot 36 with its tip or blade 41 normally projecting therefrom, and its body extending back into the wider portion 35 of the channel, terminally in frictional abutment with a pair of radially directed compression springs 39, 40, thus biased to continually urge the vanes outward into wiping contact with the inner peripheral face of the housing side wall 24. An annular gasket seal 29, 31 extends around the respective ends of the rotor.

The outer, peripheral, generally annular face 42 of the rotor is formed with a series of uniformly shaped recesses or shallow cavities 43, one between each pair of vanes 37, with an angularly abrupt or obtuse wall 44 (FIG. 3), closely adjacent the following edge of the vane (as it moves clockwise as viewed in FIG. 1 These open-face rotor recesses cooperate or align themselves with segments of a progressively constricting or tapered funnel 45 formed along the inner face of the side housing wall, so as to produce composite chambers of varying volume a, b, c, d between successive vanes 37.

Thus, in the compression phase, starting from the inlet vestibule 46, the successive chamber segments a, b, c, d have a progressively decreasing volume into which each charge of gas is successively moved by the rotor until finally the compressed charge is confined entirely in the rotor cavity 43 before delivery to the firing chamber f. Spark ignition need be used only at starting, and thereafter self-sustained continuous combustion occurs. The vane tip 41 (FIG. 3) in passing the interior opening of spark plug socket I6, is restrained from complete projection by contact with a lateral shoulder or ledge 55, which position of the vane produces a short bypass 38 through which gas from the (forward) ignited chamber transiently moves back to ignite the mixture in the subsequent chamber (43). In the expansion phase, the chambers f, h, i are increased stepwise (rather than gradually) as by relatively obtuse, or abrupt outset walls 47, 48 at the beginning of successive expansion chambers.

It will be seen that each shallow expansion chamber is shaped as an elongated (arcuate) rectangle of low (radial) height, but each chamber is of greater height than the preceding chamber. The relatively abrupt end wall at the beginning of each chamber thus allows the vane tip 41 to extend almost at once to the full height or extent of the shallow chamber and thus to receive the full expansion force of the gas against its total exposed area. There may thus be more than one power stage which produces high torque. What is meant by shallow expansion chambers may be appreciated from the following illustrative proportions. Incoming gas volume which occupies chamber a is compressed to about one-eleventh of this volume when it fills rotor recess d. To this volume, the firing chamber f then adds a space equal to about one eighth of the volume of chamber a; the next expansion chamber h adds to the volume of rotor recess 43 about three-eighths of the space of chamber a; the third or last expansion chamber i adds to the volume of the rotor recess 43, a space equal to about three-fourths of that of chamber a.

Thus it will be seen that the successive series of shallow, expansion chambers f, h, i (as well as the series of compression chambers 11, b, c, d) are each formed along the generally annular passage which lies along the interface formed by the inner edge of the casing and the outer face of the rotor, and are formed by elongated, generally parallel, longitudinally arcuate walls; that is, casing wall 49 is approximately parallel to rotor wall 50 (chamber 1'); casing wall'51 is approximately parallel to rotor wall 52 (chamber h); casing wall 53 is approximately parallel to rotor wall 54 (chamber f). It is not critical what portion of each chamber is contributed by the casing recess and what portion by the rotor recess; in fact, essentially the total volume of each chamber could be supplied by casing recesses, or alternately by rotor recesses, according to ease of fabrication. The essential feature however is the stepwise progression of (generally non-tapered or non-wedge shaped) expansion chambers whereby the gas pressure is reduced by a small fraction at each step as the motor moves to suecessively larger chambers, which however do not even in the end allow a pressure drop to near low or atmospheric pressure. The gas which is withdrawn from contact with a rotor drive element at the end of expansion is not spent gas; much more work could be obtained from it.

The rotary engine of FIGS. 4-5 provides an annular casing 60 housing a rotor 61 with power output shaft 62 and a radially directed series of sliding vanes 63, each urged outward against the inner face of the casing by a leaf spring 64. An ignition element such as a glow wire 65 is located adjacent the beginning of the single expansion chamber 66. The inner face of the casing 60, intermediate the closure plates 58, 59 and adjacent the ignition element, is formed with a bypass channel 67 which when a vane 63a comes to the position shown in FIG. 4, allows the ignited vapor of chamber 66 to flow back partway into preceding chamber 68, which may compress the gas mixture in that chamber still further, and in any event ignite it. Still further back, counterclockwise, the casing 60 provides two successive compression chambers 69, 70 which cooperate with successive recesses 71 (similar to 66 and 68) in the peripheral face of the rotor 61. Thus from a carburetor (not shown), the fuel-air mixture is introduced at the inlet 72, is compressed in successive chambers 70, 69, ignited in chamber 68, and expands in chamber 66 (which drives the rotorand its output shaft 62), and is then expelled still at high pressure through outlet 73 and by a conduit 74 is introduced into a turbine 75 where further work is obtained from it in running the turbine or supplying high pressure or heat for other uses.

The two-stage, non-combustion rotary engine of FIG. 6 has an annular casing 78 housing a rotor 79 and output shaft 80, the rotor carrying four radially outward urged, sliding vanes 81, 82, 83, 84. The rotor itself is formed without recesses and the interface chambers 88, 89, 90 are all formed in the face of the casing 78. Expandible vapor under high pressure is introduced at inlet through a line 86 from a generating or storage source 87 such as a steam boiler or air compressor. In the first chamber 88 the leading vane is moved by the compressed vapor which remains at the same pressure as in conduit 86, that is, without expansion or pressuredrop. In the succeeding chamber 89 the vapor is allowing to expand, and in the vent chamber 90 (still under high pressure) it passes out through a lateral slit outlet 91. The high pressure exhaust permits condensation at higher temperature than from normal boiler systems.

A further developed or more complex, noncombustion rotary engine is shown in FIG. 7 where the non-recessed rotor and inner-recessed casing 96 provide two complete cycles, each based on an initial non-expansion chamber 97, 98, and successive pairs of expansion chambers 99, 100 and 101, 102. As before, the succession of outwardly urged, sliding vanes 94 wipingly sweep the inner face of the casing 96 so as to carry sealed portions of expansible gas (the vanes thus acting as moving baffles traveling lengthwise with the flow stream) which seccessive discrete portions of compressed gas are moved from inlet 103 or 104 to outlet 105 or 106 as the case may be. Restriction valves 6, 7, plus throttle valves 8, 9 provide brake means, as when the engine is used to drive an automotive vehicle.

In the rotor engine construction of FIGS. 9-11, there is a tubular casing 110 externally provided with support legs 111 and cooling fins 112, and internally housing a rotor 113 and its axially extending output shaft 114. The rotor is formed in two diametric halves 115, 116 like a pair of similar cylinders having adjacent ends fastened together, axially aligned and rotatable as a whole, but with the periphery of each cylinder (115, 1 l6) having its own circumferential series of outward-sliding, axially-directed vanes 117, 118 which upon rotation of the rotor wipe the outermost walls of cavities formed about the inner face of the casing. The one series of vanes 117 and corresponding rotor and casing cavities of the left rotor half of FIG. 9 form a combustion phase (FIG. 10), and the other series of vanes 118 with their cavities form a compression phase (FIG. 11). One (left) end plate 119 of the casing is formed with a lateral inlet passage 120 which by a conduit receives the fuel-air mixture from a carburetor 122, and by successive channels 123, 124 (FIG. 9) conveys the flow to an annular cavity 125 from whence by corresponding passages 126, 127, 128, 129, 130 the flow enters an annular cavity 131 and thence by corresponding passages 132, 133 and conduit 134 is conveyed to compression inlet 135. The closed ends of the respective annular cavities 125, 131 are formed by the annular plates 136, 137, 138, 139. These two pair of plates each serve as end walls for the slots in which the series of springurged vanes 117, 118 move; however, without springs, the vanes will move outward by centrifugal force.

The inner face of the casing which surrounds rotor portion 116 is recessed to form chambers 140, 141 of successively diminishing volume, which are swept by successive vanes 118 so as to compress the air-fuel mixture as earlier described, finally forcing it through the outlets 142, 142a. By lines 143, 143a, the compression mixture is conveyed to inlets 144, 144a of the opposite rotor segment. Each charge or compound mixture contained in rotor cavity 146 is ignited by spark plug 147 and expands in casing chamber 148 from which it passes through outlet 149 to a turbine 150 or other unit. The illustrated turbine 150 (FIG. 9) is mounted on the output shaft 114 by a hub 151. The exhaust con duit 152 from the expansion phase outlets 149, 149a directs a nozzle 153 at turbine blades 154.

It will be appreciated that the turbine (75, 150) need not be on the output shaft of the rotary engine and also that the high pressure, still highly expansible gas which is withdrawn from the engine may be utilized in various ways, as well as at considerable distance from the engine. Accordingly the rotary engines of FIGS. 4-7 are shown simply as such unit as complete in itself, between the end plates 58, 59 regardless of what is subsequently done with the ejected (but not spent) gas mixture.

Solidified in the construction of FIG. 12, which is somewhat similar to that of FIG. 4, the axial output shaft 162 carries a cylindrical rotor 161 having a spokelike series of radially slidable vanes 163 outwardly urged by centrifugal force and/r socketed leaf springs 164 so that the projecting tips of the vanes sweep the inner face of the casing 160 in moving (clockwise) from adjacent an inlet 172 (flow-connected to a carburetor) through a compression chamber 170, 169 to an initial (or pre-) expansion chamber 166 and secondary expansion chamber 176, then to outlet 173 which is equipped with a restriction valve 177. The end of the generally cylindrical housing 160 is overlaid by a closure plate 158 sealingly bolted or otherwise affixed thereto. An ignition element 165 of either the sparkplug or glow-wire type is mounted in one side of the casing at the beginning of the chamber 166. in this construction, all of the compression-expansion recesses are formed in the casing (and not in the rotor), and the rotor has its peripheral face (between successive vanes 163) covered by successive segments forming a composite band or hoop 17] cast or molded thereon from an inert, homogeneous mixture of fiberous and powdered carbon. Such allotropic mixture is commercially available from The Carborundum Company under the trademark Carbitex (100 series) and is characterized by outstanding thermal-shock resistance and low thermal conductivity, resistance to corrosion or erosion, dimensional stability, high strength-to-weight ratio, and high impact and tensile strength.

The high temperature portions of the annular passage 175 which surrounds the rotor face, that is, the combustion chambers 166, 168, 176 of the casing, advantageously are formed with a facing 174 of this same inert material. If desired, the entire length of the annular passage 175 can be made of such material, thus permitting the remainder or supporting portion of the housing to be made of light weight material, such as aluminum or even synthetic plastic. Likewise, the entire rotor can be cast of such material rather than just the arcuate segments as here illustrated. Carbitex is easily machined to close tolerance with carbide tools so that even the vanes can be formed of such heatresistant material.

As an approximate measure of the frictional expansion which may advantageously be severed" from the total possible expansion (to atmospheric pressure) of a gas previously compressed, as by mechanical means or other human-directed effort, one may set a maximum of approximately one half, or a range of about oneeighth to about one-half of the initial precompressed volume. Part or all of this fraction can be used to pace the rotor, and the remaining half (or more) is again compressed to the higher density and reintroduced to the expansion chamber or chambers in a continuous process. The commonest example of such gas is air.

I claim:

1. The process for converting gaseous energy to high torque, rotary power, which process consists essentially of pacing the rotation of a drive shaft by expansion of successive portions of high pressure gas directed against a driving surface of the shaft, of which gas each portion in continuous sequence is allowed to expand only enough that its pressure is reduced only by a small fraction and it is then promptly withdrawn from further driving contact with said driving surface while still at high pressure.

2. The process of the preceding claim 1 which is effected with concurrent compustion-expansion of said successive portions of gas.

3. The process of the preceding claim 1 wherein additional rotary work is successively extracted from said withdrawn high pressure gas by further controlled expansion of the latter and at least part of such additional work is added to the rotary power obtainable from said drive shaft.

4. The process of the preceding claim 2 wherein the expansion of said successive portions of the combusdon-expanded gas is limited to about one-eighth of its previous compressed volume.

5. The process for converting potential energy of expansible gas to rotary energy of a power output shaft, which process consists essentially, in a continuous sequence of direction against a driving surface of said shaft, successive discrete volumes of expansible gas for effecting complete rotary movement of the shaft by very limited expansion of each such discrete volume, and at the same time effecting further expansion of such limited-expanded volumes by directing same against another driving surface of said shaft.

6. The process of the preceding claim 5 wherein said expansible gas is steam.

7. The process of the preceding claim 5 wherein said expansible gas is compressed air.

8. A sliding-vane rotary engine of the character described, comprising in combination:

a casing formed with a generally annular cavity therein and a generally cylindrical rotor having an axially projecting power-output shaft rotatably mounted in said cavity, the rotor carrying a circumferential series of radially outward directed sliding vanes disposed for wiping contact with the internal face of said casing between a casing inlet and outlet so as to define successive closed chambers between consecutive vanes along the peripheral interface between the rotor and casing, the walls of said interface intermittently extending generally radially so as to define consecutive, elongated, shallow, gas chambers of successively increased volume, including at least one formed by generally parallel arcuate walls radiused from the axis of said shaft, wherein an expanding gas passing from chamber to chamber upon rotation of the vanes may drive said vanes and power-output shaft in a continuous manner.

9. The rotary engine of the preceding claim 8 wherein said power output shaft additionally carries a turbine having blades disposed for driving impact by gas directed thereagainst upon emergence from said casing outlet.

10. The rotary engine of the preceding claim 8 wherein said chambers along the peripheral interface are formed at least in part in said rotor, and said casing contains a gas ignition element and is formed with a short bypass open to successive rotor chambers adjacent the ignition element, whereby ignited gas from the forward moving chamber can pass back and ignite gas in the following chamber.

11. An internal combustion, rotary engine comprising, in combination:

a casing having inlet and outlet ports and formed with a generally annular cavity therein, the periphery of which cavity contains a passage of decreasing capacity from the inlet port to adjacent an ignition element, and a second passage extending from adjacent said ignition element to said outlet port, said second passage being individually characterized by successive shallow recesses of generally parallel, longitudinally arcuate walls and stepwise increased volume aligned for expansion of gas moved by rotary vanes from one recess to the next in an expansion cycle;

a gas ignition element disposed at the beginning of said expansion cycle;

a cylindrical rotor and axially projecting poweroutput shaft jointly mounted in said cavity, the periphery of said rotor being formed with recesses of generally uniform volume which upon rotation are progressively alignable with the several recesses of the two passages of said cavity so as to move gas from the inlet port to the outlet port;

plurality of radially slidable vanes individually carried by said rotor intermediate the recesses of the rotor with their outer ends disposed in wiping registration with the periphery of said cavity, and means urging all of said vanes radially outward so as to form complete enclosures between successive vanes.

12. The rotary engine of the preceding claim 11 wherein the casing recesses of said expansion cycle are abruptly outset at their proximate edges, thereby permitting substantially immediate maximum extension of successive vanes in each such recess.

13. The rotary engine of the preceding claim 12 wherein there are at least three casing recesses in said expansion cycle.

14. The rotary engine of the preceding claim 11 wherein the recesses of said rotor are characterized by an abrupt end wall at the leading end.

15. In a device for obtaining rotary work by expansion of gas in a generally annular passage formed between the periphery of a rotor carrying extensible vanes and a surrounding housing internally wiped by said vanes, the improvement wherein said annular passage is characterized by successive shallow arcuate chambers of stepwise increased volume individually formed by generally parallel, longitudinally arcuate walls.

16. A rotary power device according to claim 15 wherein the initial chamber of said successive shallow arcuate chambers, limits gas expansion therein to about one-eighth to one-half of its previous compressed volume.

17. A rotary device according to claim 15 wherein the peripheral face of said rotor and at least the walls of the combustion chambers of the surrounding housing are each formed with an inert, homogeneouslymixed fiber and bonding matrix each formed essentially of allotropic carbon, said mixture being characterized by low thermal conductivity and corrosion resistance. I 

1. The process for converting gaseous energy to high torque, rotary power, which process consists essentially of pacing the rotation of a drive shaft by expansion of successive portions of high pressure gas directed against a driving surface of the shaft, of which gas each portion in continuous sequence is allowed to expand only enough that its pressure is reduced only by a small fraction and it is then promptly withdrawn from further driving contact with said driving surface while still at high pressure.
 2. The process of the preceding claim 1 which is effected with concurrent compustion-expansion of said successive portions of gas.
 3. The process of the preceding claim 1 wherein additional rotary work is successively extracted from said withdrawn high pressure gas by further controlled expansion of the latter and at least part of such additional work is added to the rotary power obtainable from said drive shaft.
 4. The process of the preceding claim 2 wherein the expansion of said successive portions of the combustion-expanded gas is limited to about one-eighth of its previous compressed volume.
 5. The process for converting potential energy of expansible gas to rotary energy of a power output shaft, which process consists essentially, in a continuous sequence of direction against a driving surface of said shaft, successive discrete volumes of expansible gas for effecting complete rotary movement of the shaft by very limited expansion of each such discrete volume, and at the same time effecting further expansion of such limited-expanded volumes by directing same against another driving surface of said shaft.
 6. The process of the preceding claim 5 wherein said expansible gas is steam.
 7. The process of the preceding claim 5 wherein said expansible gas is compressed air.
 8. A sliding-vane rotary engine of the character described, comprising in combination: a casing formed with a generally annular cavity therein and a generally cylindrical rotor having an axially projecting power-output shaft rotatably mounted in said cavity, the rotor carrying a circumferential series of radially outward directed sliding vanes disposed for wiping contact with the internal face of said casing between a casing inlet and outlet so as to define successive closed chambers between consecutive vanes along the peripheral interface between the rotor and casing, the walls of said interface intermittently extending generally radially so as to define consecutive, elongated, shallow, gas chambers of successively increased volume, including at least one formed by generally parallel arcuate walls radiused from the axis of said shaft, wherein an expanding gas passing from chamber to chamber upon rotation of the vanes may drive said vanes and power-output shaft in a continuous manner.
 9. The rotary engine of the preceding claim 8 wherein said power output shaft additionally carries a turbine having blades disposed for driving impact by gas directed thereagainst upon emergence from said casing outlet.
 10. The rotary engine of the preceding claim 8 wherein said chambers along the peripheral interface are formed at least in part in said rotor, and said casing contains a gas ignition element and is formed with a short bypass open to successive rotor chambers adjacent the ignition element, whereby ignited gas from the forward moving chamber can pass back and ignite gas in the following chamber.
 11. An internal combustion, rotary engine comprising, in combination: a casing having inlet and outlet ports and formed with a generally annular cavity therein, the periphery of which cavity contains a passage of decreasing capacity from the inlet port to adjacent an ignition element, aNd a second passage extending from adjacent said ignition element to said outlet port, said second passage being individually characterized by successive shallow recesses of generally parallel, longitudinally arcuate walls and stepwise increased volume aligned for expansion of gas moved by rotary vanes from one recess to the next in an expansion cycle; a gas ignition element disposed at the beginning of said expansion cycle; a cylindrical rotor and axially projecting power-output shaft jointly mounted in said cavity, the periphery of said rotor being formed with recesses of generally uniform volume which upon rotation are progressively alignable with the several recesses of the two passages of said cavity so as to move gas from the inlet port to the outlet port; a plurality of radially slidable vanes individually carried by said rotor intermediate the recesses of the rotor with their outer ends disposed in wiping registration with the periphery of said cavity, and means urging all of said vanes radially outward so as to form complete enclosures between successive vanes.
 12. The rotary engine of the preceding claim 11 wherein the casing recesses of said expansion cycle are abruptly outset at their proximate edges, thereby permitting substantially immediate maximum extension of successive vanes in each such recess.
 13. The rotary engine of the preceding claim 12 wherein there are at least three casing recesses in said expansion cycle.
 14. The rotary engine of the preceding claim 11 wherein the recesses of said rotor are characterized by an abrupt end wall at the leading end.
 15. In a device for obtaining rotary work by expansion of gas in a generally annular passage formed between the periphery of a rotor carrying extensible vanes and a surrounding housing internally wiped by said vanes, the improvement wherein said annular passage is characterized by successive shallow arcuate chambers of stepwise increased volume individually formed by generally parallel, longitudinally arcuate walls.
 16. A rotary power device according to claim 15 wherein the initial chamber of said successive shallow arcuate chambers, limits gas expansion therein to about one-eighth to one-half of its previous compressed volume.
 17. A rotary device according to claim 15 wherein the peripheral face of said rotor and at least the walls of the combustion chambers of the surrounding housing are each formed with an inert, homogeneously-mixed fiber and bonding matrix each formed essentially of allotropic carbon, said mixture being characterized by low thermal conductivity and corrosion resistance. 